Mineral-oil derivative and process of making same



Patented Dec. 11, 1928.

UNITED STATES PATENT OFFICE.

GELLERT ALLEMAN, 0F SWARTHMORE, PENNSYLVANIA, ASSIGNOR TO- SUN OIL COM-- IPANY, 0F PHILADELPHIA, PENNSYLVANIA, A CORPORATION OF NEW JERSEY.

MINERAL-OIL DERIVATIVE PROCESS OF MAKING SAME.

No Drawing.

In the manufacture of lubricating oils from crude petroleum, it is customary to subject the same to distillation and then to redistill the distillate, the heavier product remaining in the still being stock adapted for the manufacture of lubricating oil. The second distillate may then be redistilled, the part remaining also being adapted for lubricating stock. Lubricating stock is usually treated with sulfuric or. other suitable acid, with agitation, forming an acid sludge, which is fossil resins, which I hereinafter call petro-' leum resins, some sodium sulfate, and more or less water. It is known to so treat this alkaline precipitate as to eliminate some of the mineral oil, a large part of the water and most of the salts, and to materially reduce the percentage of mineral oil. However, no process has ever been devised to effect an absolute, or even a substantial, elimination of the mineral oil. I

The object of my invention is to produce a soap, derived from mineral oil, from which the mineral oil is absolutely eliminated or so nearly so that it may be said to be practic-ally free of mineral oil. I also contemplate the elimination of salts (principally or entirely sodium sulfate). My present invention, however, does not necessarily involve the elimination of the petroleum resins, inasmuch as the mixture or compound of soap and resins is adapted to a wide variety of commercial uses, provided it is freed of the mineral oil.

In specially describing the process, embodying my invention, whereby I eliminate the oil, it will be understood that I am merely giving an example and that the statements therein made as to the composition of the alkali precipitate, temperature, pressure, etc., are predicated upon the treatment of a composition having definite proportions of certain ingredients and produced in the'abave described treatment of lubricating oil stock Application filed February'G, 1924. Serial No. 691,022.

derived from Texas oil. It will also be understood that even with this particular crude petroleum, difierent distillation processes, and even variations in the same distillation process, as well as variations in the crude oil, would yield alkali precipitates of varied compositions and characteristics, making advisable some variation from the'specilic example of the process herein given, in order to secure the elimination of the mineral oil to the highest degree. Experiments, however, will enable a skilled operator'to so adjust the factors of time, temperature, pressure and percentage of water added, as to secure the result sought-the substantially complete elimination of the mineral oil.

A typical composition of the alkali precipitate (soda sludge) which I have treated and from which I have succeeded in eliminating the mineral oil, is as follows:

Per cent. Soap 11. (3 Petroleum resins 17. 1 Mineral oil 46. Sodium sulfate 2.3 Water 23.

sixty pounds during the cooling process. A-

perfect separation takes place. On the top will be found a layer of oil; on the bottom a water layer containing soap, resin and sodium sulfate.

\Vitli the above composition, it is impor- 9 tant thatthe specified percentage (58) of water should be adhered to quite closely. While, if more or less water he added, a separation of the oil takes place, the amount of soap obtained is not as great. The percentuted for compressed air, as, for example, any inert gas such as nitrogen. Withoutsuch operation, the oil separates on the top, and the soap, resinous material and sodium sulfate remain in solution at the bottom; but when the mixture cools, a vacuum is created and the whole mass boils violently. In consequence of this boiling, the soap, oil and sodium sulfate again enter into the emulsion stage. Under these conditions, no permanent separation occurs. When, however, cooling takes place under pressure, the mass does not boil, and the separation is permanent.

The pressure of the compressed air 1s governed by the temperature during the cooling process. The pressure of the air must be suflicient to prevent boiling of the contents of the boiler. When the steam pressure is cut off, the air pressure must equal the steam pressure. As cooling proceeds, the air pressure may be reduced to such an extent as w ll ust prevent boilin Therefore where, 1n the claims, I specify cooling under pressure, or under pressure corresponding to the preceding steam pressure, it is not intended to require that such pressure shall be maintained throughout the cooling.

The sodium sulfate remaining in the soap 1s usually objectionable. Therefore, after its removal from the boiler, the soap and resin solution is concentrated, by evaporating some of the water, and is then cooled in order to separate the soap and resin from the sodium sulfate. The separation begins to take place at about 5 'C.. and is hastened by lower temperatures. It is found that the soap and resin which first separates has a higher resin con tent than that which separates finally. This suggests that the resin is less soluble than the soap. The soap and resin solidify to a pasty mass. The sodium sulfate remains in solution in the Water.

As hereinbefore stated, changes in the composition of the alkali precipitate (soda sludge) will necessitate slight changes in the amount of water to be added, the time of steaming, and the pressures to be applied.

While the principal object of the invention is to entirely eliminate mineral oil from the soap and resin while recovering the maximum proportion of the latter, the mineral lubrieating oil that separates out is of high quality and therefore of substantial commercial value.

It should be understood that the claims are not limited to the precise order in which the steps of'the process are recited except to the extent that such precise order is necessarily implied or is essential to operativeness.

The oil-free mixture or compound of soap and resinous material has the characteristics of the saponified derivative set forth in the Maitland Patent No. 1,425.884, dated August 15, 199.2, in that it is miscible in all proportions with water or mineral oil and has essential characteristics of soaps of animal or 'mixed with mineral oil and water. it forms a homogeneous emulsion. It is distinguishable, however, from soaps of animal or vegetable origin in that it is a liquid and stick its stickiness being probably due to its su stantial content of petroleum resins. It is distinguishable from known saponified derivatives from mineral oil by its substantially entire freedom from mineral oil. Indeed, I have succeeded in an absolutely complete elimination of the oil, although in some runs there remains a verysmall percentage that would properly be designated a trace.

If it be desired to separate the oil-free, unsaponified fatty acids, the saponification number of the oil-free sodium soap is determined, and to the soap I add just the amount of sulfuric acid or hydrochloric acid necessary to break down the soap. This product has the characteristics of the saponifiable mineral oil derivative set forth in the Maitland patent aforesaid; that is, it is insoluble in water, is practically odorless, does not become rancid, and the sulfur content is extremely low, I having succeeded in reducing it to less than one hundredth of one per cent. This separated unsaponified but saponifiable substance, which is of the nature of a fatty acid, is distinguishable from known so-called fatty acid or organic acid derivatives of mineral oil in that it is substantially or entirely free from mineral oil.

The isolation of this mixture of fatty acids and petroleum resins, and of the mixture of fatty acid soap and petroleum resins, has never been heretofore accomplished; such substances never having been derived heretofore from petroleum except in admixture with a very substantial proportion of mineral oil. In the manufacture of products containing these fatty acids or their soaps and from which the complete or substantial exclusion of mineral oil is necessary, in which'more than a small proportion of mineral oil is objectionable, it is believed that no other product is available except that which I have succeeded in isolating.

Having now fully described my invention, what I claim and desire to protect by Letters Patent is:

1. The process of treating a composition containing mineral oil. petroleum resins and a fatty acid soap and having the characteristics of the precipitate produced in the alkali treatment of acid-treated mineral oil lubricating stock, to effect a substantially complete separation of the oil from the soap and resins,

which comprises adding Water to the coma fatty acid soap po; ition and heating under suflicient pressure to separate the oil from the soap and resins, cooling under siifiicient pressure to prevent substantial boiling and the re-entry of the oil, and resins and soap into the emulsion stage, and removing the oil.

2. The process of treating a composition containing mineral oil, petroleum resins and a fatty acid soap and having the characteristics of the precipitate produced in the alkali treatment of acid-treated mineral oil lubricating stock, to efi'ect a substantially complete separation of the oil from the soap and resins, which comprises adding water, heating at a steam pressure of substantially above two atmospheres, thereby effecting separation of the oil from the soap and resins, cooling, and during cooling superimposing com.- pressed air to prevent substantial boiling and the re-entry of the oil, and resins and soap into the emulsion stage, and removing the oil.

3. The process of treatin a composition containing mineral oil, petro euin resins and and having the characteristics of the precipitate produced in the alkali treatment of acid-treated mineral oil lubricating stock, to effect a substantially complete separation of the oil from the soap and resins, which comprises adding to the composition a percentage of water which, in addition to the water already present therein, will make its water content approximate fift -e1ght per cent, heating under pressure to e ect separation of the oil from the soap and resins, cooling under pressure to maintain the oil separated from the soap and resins, and removing the oil.

4. The process of treating a composition containing mineral oil, petroleum resins and a fatty acid soap and having the characteristics of the precipitate produced in the alkali treatment of acid-treated mineral oil lubricating stock, to effect a substantially complete separation of the oil from the soap and resins, which comprises adding water, heating'ainder pressure, thereby efi'ecting separation of the oil from the soap and resins, cooling under pressure to maintain the oil separated from the soap and resins, and removing the oil; the percentage of water contained in the material preparatory to heating being so adjusted as to effect a maximum recovery of soa 5? The process of treating a. composition containing mineral oil, petroleum resins and fatty acid soap and having the characteristics of the precipitate produced in the alkali treatment of acid-treated mineral oil lubricating stock, to effect a substantially complete separation of the oil from the soap and resins. which comprises adding water, heating at a steam pressure of not less than approximately four atmospheres, thereby effooting separation of the oil from the soap and resins, cooling, and during cooling superimposing compressed air at a pressure of approximately tour atmospheres to maintain the'oil separated from the soap and resins,

and removing the oil.

6. The process of treating a composition containing mineral oil, petroleuiniresins and a fatty acid soap and having the characteris tics of the precipitate produced in the alkali treatment of acid-treated mineral oil lubricating stock, to efi'ect a substantially complete separation of the oil from'the soap and resins, W ich comprises adding to the composition a percentage of water which, in addition to the Water present therein, Will make its water content approximate fifty-eight per cent, heating at a steam pressure of substantially more than two atmospheres until the oil is practically completely separated from the soap and resins, cooling, and during cooling superimposing compressed air at a pressure substantially corresponding to the preceding steam pressure, thereby maintaining the oil separated from the soap and resins, and removing the oil.

7. The process of treating a composition containing mineral oil, petroleum resins, fatty acid soap and an inorganic salt having the characteristics of the precipitate produced in the alkali treatment of acid-treated mineral oil lubricating stock to eflect the separation derivative from mineral oil, the same being a composition containing soap and petroleum resins and miscible in all proportions with water and mineral oil, and when mixed with mineral oil and Water forming a homogeneous emulsion, and having essential characteristics of soaps of animal and vegetable origin in that it forms with water a similar colloidal suspension and undergoes the same character of hydrolytic decomposition; the new prodnot being distinguishable from soaps of animal or vegetable origin in that it contains a large proportion of petroleum resins, and being distinguishable from other soaps derived 'from mineral oil in that in addition to the characteristics specified it is substantially free of mineral oil.

9. As a new product, the herein described derivative from mineral oil, the same being insoluble in Water, practically odorless, and readily saponifiable, the same being distinguishable from animal or vegetable fatty acids in that it contains a substantial proportion of petroleum resins and does not become rancid, being distinguishable from sulfonic acids in that any sulfur that it may contain is present in a proportion much less than one per cent and that when saponified with an alkali it undergoes the same character of hydrolytic decomposition that occurs with soaps of animal or vegetable origin, and being distinguishable from other saponifiahle derivatives from mineral oil in that it is substantially entirely free from mineral oil.

In testimony of which invention, I have hereunto set my hand. at Swarthmore, Penna, on this 31st day of J anun'ry, 1924.

GELLERT ALLEMAN. 

